<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title></title>
		<script>
			var st="hello,world"
			var st1=st.substr(2);//表示从下标2开始往后截取
			var st2=st.substring(2,5);
			var st3=st.substr(2,5);//表示从下标2开始往后截取,5表示截取字符个数
			var st4=st.charCodeAt(5);
			var st5=String.fromCharCode(69,68,100);
			document.write(st1+"<br />");
			document.write(st2+"<br />");
			document.write(st3+"<br />");
			document.write(st4+"<br />")
			document.write(st5)
		</script>
	</head>
	<body>
	</body>
</html>
